A common and desirable method of treating a cataract eye is to remove the clouded, natural lens and replace it with an artificial intraocular lens (IOL) in a surgical procedure known as cataract extraction. In the extracapsular extraction method, the natural lens is removed from the lenticular capsular bag while leaving the posterior part of the capsular bag (and preferably at least part of the anterior part of the capsular bag) in place within the eye. In this instance, the lenticular capsular bag remains anchored to the eye's ciliary body through the zonular fibers. The capsular bag also continues its function of providing a natural barrier between the aqueous humor at the front of the eye and the vitreous humor at the rear of the eye.
Another trend in modern day cataract surgery is the reduction of the corneal incision size because larger incision sizes have been attributed to unwanted post-surgical conditions such as incision-induced astigmatism. IOLs and IOL inserters capable of successfully inserting the IOL through a sub 2.5-mm incision is desired by most cataract surgeons. Because the IOL undergos compression and other forces as it is passed through the IOL inserter, the dimensions (particularly the cross-section) of the IOL must accordingly be minimized. An IOL designer is thus further challenged in making an IOL that will have the strength and stability to remain centered in the eye, yet has a dimensional size and mechanical flexibility at near room temperature to pass through a sub-2.5 mm incision size. It will be appreciated that these are often competing design goals in that reducing IOL dimensions to fit within a smaller incision can result in a decrease in the strength and stability of the IOL in the eye.
The strength and stability of the IOL within the eye is of course crucial in obtaining and maintaining the intended vision correction expected by the physician and, more importantly, the patient. Accordingly, there remains a need for an improved IOL design that is dimensioned to fit through a sub-2.5 mm incision, and yet, is positionally stable in the capsular bag for many years following the surgery. It is also, important to the physician that the IOL have the ability to self-center within the capsular bag to minimize the amount of physical manipulation of the lens following insertion of the lens.